tonight begins a weeklong focus on guns here on pbs, "after newtown." on the newshour this evening, we look at political and other developments since the december tragedy and zero in on the gun debate in colorado. >> in the divisive atmosphere of the gun debate, both sides, at the federal and state level, say they know the coming months won't be easy. but they will be critical. >> ifill: then, we take up the arguments for and against the proposed construction of the keystone pipeline, as environmental activists mounted a protest this weekend. >> woodurff: ray suarez updates the hugo chavez story, after the president's surprise return to venezuela following more than two months of cancer treatment in cuba. >> ifill: and jeffrey brown talks with filmmaker kirby dick about his oscar-nominated documentary "the invisible war," detailing the high rate of sexual assault in the u.s. military. >> 86% of men and women who are sexually assaulted in the military don't report. they experience reprisals that are, in many ways, a second betrayal that's even worse than